1. Field of the Invention
The present invention relates to a method for manufacturing a silicon carbide semiconductor device, and more particularly to a method for manufacturing a silicon carbide semiconductor device having the step of forming a silicon dioxide film on a silicon carbide substrate.
2. Description of the Background Art
In recent years, silicon carbide substrates have come into use to manufacture semiconductor devices. Silicon carbide has a band gap larger than that of silicon. Accordingly, a semiconductor device using a silicon carbide substrate has advantages such as high breakdown voltage, low ON resistance, and less deterioration of characteristics under a high temperature environment.
International Publication No. 2009/128419 discloses an ohmic contact electrode which is arranged in contact with a SiC wafer (silicon carbide substrate) and contains titanium (Ti) and aluminum (Al) as materials. According to the publication, contact resistance to the SiC substrate can be reduced by using the above materials.
However, when an electrode containing Ti and Al is adopted, there have been cases where insulation reliability of an insulating film may be decreased.